rockbox/apps/plugins/sdl/progs/quake/dosasm.S
Franklin Wei 5d05b9d3e9 Quake!
This ports id Software's Quake to run on the SDL plugin runtime. The
source code originated from id under the GPLv2 license. I used
https://github.com/ahefner/sdlquake as the base of my port.

Performance is, unsurprisingly, not on par with what you're probably
used to on PC. I average about 10FPS on ipod6g, but it's still
playable.

Sound works well enough, but in-game music is not supported. I've
written ARM assembly routines for the inner sound loop. Make sure you
turn the "brightness" all the way down, or colors will look funky.

To run, extract Quake's data files to /.rockbox/quake. Have fun!

Change-Id: I4285036e967d7f0722802d43cf2096c808ca5799
2019-07-19 22:37:40 -04:00

77 lines
1.2 KiB
ArmAsm

#include "asm_i386.h"
.data
fpenv: .long 0, 0, 0, 0, 0, 0, 0, 0
.text
.globl C(StartMSRInterval)
C(StartMSRInterval):
movl $0x11,%ecx // read the CESR
.byte 0x0F
.byte 0x32 // RDMSR
andl $0xFE3FFE3F,%eax // stop both counters
.byte 0x0F
.byte 0x30 // WRMSR
movl 4(%esp),%eax // point counter 0 to desired event, with counters
andl $0x3F,%eax // still stopped
movl $0x11,%ecx
.byte 0x0F
.byte 0x30 // WRMSR
movl $0x12,%ecx // set counter 0 to the value 0
subl %eax,%eax
subl %edx,%edx
.byte 0x0F
.byte 0x30 // WRMSR
movl 4(%esp),%eax // restart counter 0 with selected event
andl $0x3F,%eax
subl %edx,%edx
orl $0xC0,%eax
movl $0x11,%ecx // control and event select
.byte 0x0F
.byte 0x30 // WRMSR
ret
.globl C(EndMSRInterval)
C(EndMSRInterval):
movl $0x12,%ecx // counter 0
.byte 0x0F
.byte 0x32 // RDMSR
ret // lower 32 bits of count in %eax
#if 0
.data
Lxxx: .long 0
.text
.globl C(setstackcheck)
C(setstackcheck):
movl %esp,%eax
subl $0x38000,%eax
movl $0x5A5A5A5A,(%eax)
movl %eax,Lxxx
ret
.globl C(dostackcheck)
C(dostackcheck):
movl Lxxx,%edx
movl $0,%eax
cmpl $0x5A5A5A5A,(%edx)
jz qqq
incl %eax
qqq:
ret
#endif